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Discussion Starter · #1 ·
I originally printed from Illustrator. Artwork is CMYK with C=0,M=0,Y=0,K=100.

I believe I have all the print options cranked to max quality however if I look super closely at my film positive, curves are not smooth. From a normal viewing distance my film print looks awesome but the effect seems to be magnified by the time I expose a screen and then use ink. I output a 1600dpi PNG from Illustrator and printed from Photoshop. That actually improved the edges however I can still detect some saw tooth effect. I've exposed enough screens to know it's still too jagged for a nice print with ink. I'd take a photo with my phone however It won't be high res enough to make out what I'm referring to.

Anyone using this printer able to help me out? Thanks!
 

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Artwork is CMYK with C=0,M=0,Y=0,K=100.
a) The Pixma ix6820 is not a postscript printer, so you should print in RGB mode.
b) even with a postscript printer, you will get better results with C=100,M=100,Y=100,K=0. The black is pigment ink. Dye inks work much better.
 

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Discussion Starter · #3 ·
a) The Pixma ix6820 is not a postscript printer, so you should print in RGB mode.
b) even with a postscript printer, you will get better results with C=100,M=100,Y=100,K=0. The black is pigment ink. Dye inks work much better.
Thanks for the reply! So you'd suggest printing straight from illustrator after converting my document to RGB and changing my black to the values shown? I'll try that and report back thanks again.
 

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Discussion Starter · #4 ·
a) The Pixma ix6820 is not a postscript printer, so you should print in RGB mode.
b) even with a postscript printer, you will get better results with C=100,M=100,Y=100,K=0. The black is pigment ink. Dye inks work much better.
Alright I changed my document in Illustrator to RGB and set my black as you suggested. To be honest I'm not seeing any improvements but maybe I'm doing something else wrong?

Here's a picture showing the edges: https://doodlebrains.net/images/sawtooth1.jpg

Other print settings I've changed as per some suggestions from YouTube users with this printer:

Grayscale printing: selected
Media Type: Photo Paper Pro Platinum
Print quality: Custom (1 - Fine)
Color/Intensity: Manual (Intensity - 50/Dark and Contrast - 50/High)

Any of these settings not ideal? Any other thoughts?

Thanks again!
 

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I print out of CorelDraw to AccuRIP, so can't suggest specific AI settings as I'm not familiar with it. But I would double-check the image dimensions and output resolution in AI to see if they make sense. Sometimes applications like to automatically change one when you change the other, locking you into the same number of overall pixels unless your override it. I doubt the printer is adding jaggies that weren't in the art itself.
 

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Yeah... that's definitely not good.

Any of these settings not ideal? Any other thoughts?
It is definitely postscript related, but I don't know how to get around it from within illustrator.
It is a known issue by the way...Source.
When you print from Illustrator to a non PostScript printer, objects may not print, or may print incorrectly.
You can try the following:
a) exporting to PDF and print it this way, OR
b) export it to svg and use Inkscape (free software).
 

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Discussion Starter · #7 ·
Yeah... that's definitely not good.


It is definitely postscript related, but I don't know how to get around it from within illustrator.
It is a known issue by the way...Source.
You can try the following:
a) exporting to PDF and print it this way, OR
b) export it to svg and use Inkscape (free software).
Thanks for all the help. So far the only thing that has made a visible improvement has been to continue printing a PNG from Photoshop. I was able to output as high as 1900dpi but the edges are still not as smooth as they should be. I was printing as RBG in Photoshop. Printing from a PDF was better than direct from Illustrator but certainly worse than from Photoshop.

Something I'm wondering... the saw tooth seems to be more obvious if I'm looking at the film from the non-ink side. Does it matter when you're exposing, which way the film positive is laid down on the glass?
 

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Discussion Starter · #8 ·
I print out of CorelDraw to AccuRIP, so can't suggest specific AI settings as I'm not familiar with it. But I would double-check the image dimensions and output resolution in AI to see if they make sense. Sometimes applications like to automatically change one when you change the other, locking you into the same number of overall pixels unless your override it. I doubt the printer is adding jaggies that weren't in the art itself.
The artwork is vector so I can zoom as much as I want within Illustrator and the edges are nice and smooth. It seems to be the way the printer is interpreting those vector edges that cause issue.
 

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It seems to be the way the printer is interpreting those vector edges that cause issue.
Correct, because illustrator is postscript optimized, and your printer does not support it.
Try the bitmap mode File > Print > Advanced and select 'Print As Bitmap'.

Does it matter when you're exposing, which way the film positive is laid down on the glass?
It does. the film has to be printed side up (touching the screen).
 

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Discussion Starter · #10 ·
Correct, because illustrator is postscript optimized, and your printer does not support it.
Try the bitmap mode File > Print > Advanced and select 'Print As Bitmap'.


It does. the film has to be printed side up (touching the screen).
I'd already given that print as bitmap a try thanks. Still nowhere close to as good as the high dpi png out of Photoshop.

I'd seen this printer suggested in quite a few places by screen printers... this is quite a bummer!

I'm going to try some new exposures with the best film positive I've got ensuring it's ink side up (my recent attempts were all ink side down).
 

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The artwork is vector so I can zoom as much as I want within Illustrator and the edges are nice and smooth. It seems to be the way the printer is interpreting those vector edges that cause issue.
Yes, understood, CD is also vector. I was trying to suggest that the problem was in the way AI was sending the art to the printer. For example, when exporting/outputting to a PNG, AI determines how the vector objects are converted to pixels. There are no doubt settings regarding smoothing and anti aliasing and the like.

Sounds like Tabob knows specifically what he is talking about, as opposed to my generalized guessing.
 

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Discussion Starter · #12 ·
Yes, understood, CD is also vector. I was trying to suggest that the problem was in the way AI was sending the art to the printer. For example, when exporting/outputting to a PNG, AI determines how the vector objects are converted to pixels. There are no doubt settings regarding smoothing and anti aliasing and the like.

Sounds like Tabob knows specifically what he is talking about, as opposed to my generalized guessing.
You guys both know what you're talking about thanks for the input! I'm hoping my next round of exposures will be good enough. The SVG in Inkscape combo ended up being about the same as from Illustrator directly for me. The 1800 dpi png from Illustrator (with fine art anti-aliasing) printed from Photoshop is the best I've been able to get today. That combined with having the ink side of the film against the screen (God I hope that is important enough to make a big difference!) might just be enough. Guess I should have gotten the Epson 1430. If this doesn't pan out... I still might.
 

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I'd seen this printer suggested in quite a few places by screen printers... this is quite a bummer!
True, because these are good printers for the job.

The SVG in Inkscape combo ended up being about the same as from Illustrator directly for me. The 1800 dpi png from Illustrator (with fine art anti-aliasing) printed from Photoshop is the best I've been able to get today.
Hmm... Have you done a printhead alignment?
 

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Discussion Starter · #14 ·
True, because these are good printers for the job.


Hmm... Have you done a printhead alignment?
Well my faith is renewed.After wasting a bunch of 13x19 films printing the specific area of my print that showed the worse sawtooth (in my attached pic) I got the bright idea to refeed a single film and just shift the art down. Sometimes I just don't think. So in this way I could compare on the same film various settings. I discovered something really weird after trying various paper settings, dpi etc.

The only paper type that allows for a quality setting of 1 (fine) was the Photo Paper Pro Platinum. Prints were darkest when the quality was at its finest. I could see no difference when all things were equal when toggling the print greyscale on or off. The real shocker was that after comparing 300, 600, 900, 1200 and 1800 dpi prints on the same film, the 600 was hands down the best. My film looks great now. I don't know why but what matters I guess is that I have a process now that at least is working for me. Will expose tomorrow and hopefully move on to finally making prints!

Thanks for the help guys.
 

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Discussion Starter · #15 ·
Just an update to this issue I'm having. I exposed a pair of 230 and a single 305 for comparison with my new and improved film positive. I washed one 230 out with my garden sprayer, the other with my pressure washer turned off (still stronger than garden hose). Somehow there is some minimal saw tooth in some problem areas on the 230s and far less but a hint on the 305. I'm not sure how at this point. I've got 50+ lbs of weight on my foam when exposing, my film is dark and edges appear nice and refined. See tonight what the slight toothing will mean for actual prints.
 

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Somehow there is some minimal saw tooth in some problem areas on the 230s and far less but a hint on the 305. I'm not sure how at this point. I've got 50+ lbs of weight on my foam when exposing, my film is dark and edges appear nice and refined.
Try these:
a) after the emulsion has dried, apply another coat on the bottom side and let it dry again upside down.
b) Ensure the emulsion is really dry. This is tricky and often overlooked.
c) Use an exposure calculator to find the optimal exposure time for the particular mesh.
d) When washing the screen, wet the inside but only apply pressure from the bottom side.
 

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Discussion Starter · #17 ·
Try these:
a) after the emulsion has dried, apply another coat on the bottom side and let it dry again upside down.
b) Ensure the emulsion is really dry. This is tricky and often overlooked.
c) Use an exposure calculator to find the optimal exposure time for the particular mesh.
d) When washing the screen, wet the inside but only apply pressure from the bottom side.
Thanks for the additional tips. So you're referring to a face coat right? I am already doing 2/2... what would be the benefit of the extra coat once everything is dry? I have been letting my screens dry for about 12 - 16 hrs usually before exposing (and I have used the 21 step stouffers and have gotten a 7 so I should be ok for time). I have had troubles washing out finer details however so based on some advice I'd gotten, I submerge my screens for 2-3 mins before doing my washout. I have however been spraying both sides with the garden sprayer so I will do some additional tests with my remaining 230s to see if I can't improve things a bit. I don't think I should need the 305 but it did produce prints I am happy with tonight. The plan is to just use 305 unless I can boost the quality of the remaining 230s I have coated (4 tries left before I just go shopping for 305s lol). I didn't mention it but I am printing on art paper not t-shirts.
 

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The real shocker was that after comparing 300, 600, 900, 1200 and 1800 dpi prints on the same film, the 600 was hands down the best.
I've never noticed much of a difference, but printer drivers do have predefined ppi values for each quality setting.

So you're referring to a face coat right? I am already doing 2/2... what would be the benefit of the extra coat once everything is dry?
Yes face-coat.
I prefer 1/1 and an additional face-coat once dry. Just try it and you will see the difference.
Helps with pinholes as well.

I have been letting my screens dry for about 12 - 16 hrs
Screens can actually dry in 30-40 minutes under optimal conditions.
Optimal is not necessary of course, but it does help.

have used the 21 step stouffers and have gotten a 7 so I should be ok for time
Probably good enough for vector designs, but an exposure calculator printed with the film and inks you are actually using is better.

I submerge my screens for 2-3 mins before doing my washout.
I don't think this is a good idea.
The emulsion on the squeegee side is not fully cured without post-exposure.
 

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Discussion Starter · #19 ·
I don't think this is a good idea.
The emulsion on the squeegee side is not fully cured without post-exposure.
So you do wet both sides of your screens and then only spray out on the substrate side?

I've read in a few places that a properly exposed design should wash out without a lot of pressure and in like 30-45 sec. I've found that with my already very quick exposure (8 seconds) that I cannot easily wash out thinner lines or the ends of lines that come to points unless I do that pre-soak (which was recommended to me elsewhere). I'm finding everyone seems to have their own idea of how best to do certain things... makes it tough to find the way lol. But every piece of advice I've received I have tried. I will try what you've suggested thanks!
 

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I've read in a few places that a properly exposed design should wash out without a lot of pressure and in like 30-45 sec. I've found that with my already very quick exposure (8 seconds) that I cannot easily wash out thinner lines or the ends of lines that come to points unless I do that pre-soak (which was recommended to me elsewhere).
Simple designs can be done in 45 seconds, but halftones need a bit more time and a pressure washer does help.
I only use the pressure washer for 20 seconds or so, to clear stubborn halftones or thin lines.

I guess there's more than one way to skin a cat, but if you have difficulty washing out your screens consider trying diazo emulsion.
The longer exposure time makes it much more forgiving.
 
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